I prepare my content directly as an HTML file, rather than going through Windows, and my experience has been generally good. But now I plan to include audio clips and found out that the <audio> tag is not supported, although the Amazon Kindle Publishing Guidelines state that most HTML 5 features are supported. Does anybody know how to do this for Kindle books, or if it is possible at all?

BTW It is extremely easy in iBooks Author--I've just added clips to the iBooks version of my book--and am now exploring ways to do the same for the Kindle version.

As stated on page 41 of Amazon Kindle Publishing Guidelines:“Currently, only Kindle for IOS supports audio and/or video content. Kindle e Ink devices and Kindle Fire do not support Kindle Editions with Audio/Video. To add audio and/or video content to your Kindle book, follow the guidelines and examples below.
The file delivered to Amazon should be an EPUB...
So it looks like if you upload an e-pub with audio/video, it should work. But your book will only be useable on ios based appliances.
Just because there is support for a feature using html standards, it doesn’t mean that Amazon/Kindle/KDP will universally accept it. The fact that you find it so easy to do could very well be the reason Amazon doesn’t give it a more broad-based support. Of course audio and video are going to rapidly impact the size of your book and increase download fees. Some people report ongoing KDP server issues during upload, perhaps indicating hardware support strains on the part of Amazon. It's a slow path forward.

Just because KFHD supports it, it doesn’t mean you can self-publish it.
If a big name publisher wants Amazon to support its multimedia book, I’m sure Kindle HD will. Big name publishers have their own editors/proofreaders/programmers. KDP self-publishers will still be out of luck, except perhaps being limited to iOS support at this time. Think about it, if you were Amazon/KDP, how would you be able to assure all type written, audio and video files being uploaded for sale met any Terms of Service Agreement/Standards?
You’ll be able to make it work when Amazon figures out how to make it work.

I've also been trying to figure this out. I've been in contact with Vook about formatting my enhanced ebook in KF8. They indicate that you have to have an "Amazon distributor account" in order to deliver enhanced ebooks. I haven't been able to find any information on setting up such an account for a small, independent publisher.

You have to apply to Amazon to become a "publisher," not via KDP, but as Random House, etc. They'll give you an application, and it's rather involved; they ask you, if memory serves, for the top 25 titles in your catalog (of books), how much they're selling (number of copies per annum), etc. Most small indie publishers don't rise to the annual book volume level (sales) that Amazon is seeking, as approved Publishers have access to a number of professional tools and upload mechanisms that require specialized skills and a labor force to use them (uploading via FTP, say, as well as not requiring tech support for bookmaking, or embedding audio/video, that sort of thing).

Does that help?

Hitch
We produce ebooks
Listed as an Amazon Professional Conversion Service: http://bit.ly/uFwMwb
An INScribe Preferred Conversion Partnerhttp://www.booknook.biz/
Follow me on Twitter: @BookNookBiz
"If you think it's expensive to hire a professional to do the job, wait until you hire an amateur."

Basically it uses hyperlinks from the word doc, to the video or sound file - for video I stream though a dedicated website from You Tube...this means my website doesn't suffer any bandwidth penalty, which can be expensive - one production has access to more than 20 hrs of video. With sound I do the same See http://www.coffeebook.com.au

Video links to about 20 hrs of video - some available in the Look Inside.The Great Space Race

That isn't embedded audio or video. That's simply embedding links to Youtube or other video content, which is what everyone on Amazon does. I'm sure that the poster who asked appreciates this tip, though.

To the original poster and posters: actual audio/video embedding is not available to self-publishers via the KDP. I'd put up another answer, but of course, it got sucked into the vortex.

Hitch
We produce ebooks
Listed as an Amazon Professional Conversion Service: http://bit.ly/uFwMwb
An INScribe Preferred Conversion Partnerhttp://www.booknook.biz/
Follow me on Twitter: @BookNookBiz
"If you think it's expensive to hire a professional to do the job, wait until you hire an amateur."

for video I stream though a dedicated website from You Tube...this means my website doesn't suffer any bandwidth penalty, which can be expensive

***

yes that used to be the case but over last few years most hosting companies offer unlimited space so we don't have to be tied into the nasty Google/UTube conglomerate with all that advertising and inducements to grab your customer and take him/her "down the rabbit hole".

also glad you refused to salute Gorton - you sound like you were born same as me in 1945?

With the first book, we opted to stream through our own site for several reasons - one as stated. The other was gaining the rights to the videos - I think the total is over 20 hours linked and streamed. If we had the rights we could have opted as you say to stream from our site, but unlimited bandwidth costs around $100 or more per month here, and the mutli hosting we already have was limited. The downside are the adverts etc, but in the trial stages it's tolerable.

One benefit that might be considered by authors who have You Tube promos and previews, would be linking those to their book - maybe so they can be activated from the look inside. There's a lot of scope here for innovation..